Capacitive switch solutions

Capacitive switch solutions

A strong up and coming technology is capacitive sensing. As we getting more and more used to touchscreens behind glass (mobiles, tablets, etc.), switching behind glass attracts the interest of the industry. If one takes into account the possibilities switching behind a cover lens gives, it is clear that capacitive sensing technology is recognized as future proof. With the glass examples we have produced we have demonstrated the following advantages:

Many applications still use membrane switch technology which is based on polyester graphical overlays with a switching layer underneath. This technology is not suitable to be used with a glass cover lens. Capacitive sensing is the solution to overcome this problem. With the use of a sensing layer and a microcontroller we can operate switches behind glass or other surfaces.

At SCHURTER we have three capacitive switch products to meet our customers demands and wishes.

CapKey®

The SCHURTER CapKey® is the future switch for glass operating panels. Many equipment nowadays would like to use the benefits of modern looking glass surfaces and easy to clean material. CapKey® technology is developed to make a reliable switching panel behind glass. You can use your selected graphics to print keys in any size and shape. The CapKey® technology makes use of standard available controller chips. This makes CapKey® your ideal, cost effective solution to switch behind glass!

The SCHURTER ClearCap is the ideal solution for small equipment with a simple menu structure. The ClearCap gives you all the benefits of a PCAP touchscreen in a simplified build. With a ClearCap solution you can create a modern attractive design with effective costing. This all comes as a custom design in order to fulfil your specific needs!

The SCHURTER Metal over Cap is the ideal solution for durable switches without mechanical parts. Based on the capacitive technology, SCHURTER created a switch panel for the ruggedized market. This switching technology is a good alternative for the well-known Piezo switch. The mechanical properties of the Piezo switch and the flexible options of capacitive technology meet here in one product. This all comes in a custom design in order to fulfil your specific needs!

One of the essential components within a CapKey® solution is the sensor. The sensor can be made of polyester or directly tracked on a PCB. The tracks and layout of the sensor is essential for good functionality. Transparent switch areas are possible with the use of conductive transparent material (ITO). The sensor itself will be laminated behind the chosen cover lens material. Each sensor requires a connection tail made of polyester or Kapton material. As the sensors are made by a screen print process, sensors can be produced in any required size and shape. This will give you similar design freedom as a traditional membrane switch.

Controller

Unlike PCAP touchscreens with limited number of available controllers, there are many different kind of capacitive switch controllers on the market. SCHURTER has selected, based on experience and knowledge, a preferred list of such controllers. These controllers are from well known manufacturers like Atmel, Microchip, Cypress and Freescale. Each controller has its own unique set of features and specifications. Before we can help you with the design of the correct sensor and selecting the corresponding controller, a decision has to be made of the required features like:

• Number of keys

• Sliders

• Wheels

This selection determines the most suitable controller and the required sensor design. SCHURTER provides the necessary documents and libraries for a capacitive switch design to integrate the controller onto your own PCB.

Applications

Capacitive switch products are relatively new in the industry. They can replace membrane switches and easily combine with a PCAP touchscreen. They are also perfectly suitable to make equipment with a modern look and feel. It also introduces new features like sliders and wheels. An ideal technology for state of the art medical equipment.